Forms for the 2006 census, due to take place next month, will be translated into 11 foreign languages and will ask people about their ethnic or cultural background for the first time, Carl O'Brien, Social Affairs Correspondent.
Officials at the Central Statistics Office expect the results will show that up to 10 per cent, or 400,000 people, are foreign nationals. This figure is similar to countries with a long history of immigration, such as the US and Britain.
Statisticians also say the overall population may reach 4.2 million, the highest level in 135 years. The 1871 census recorded a population of 4.1 million.
Launching an awareness campaign yesterday for the census - which takes place on the night of Sunday, April 23rd - Taoiseach Bertie Ahern said there was no reason for any ethnic group to feel fearful about filling out the form.
"Everyone can be fully assured that all information given will be treated as strictly confidential," Mr Ahern said. "It will be used for statistical purposes only and the results will be prepared and disseminated in a fair and impartial manner."
Under the question of ethnicity, respondents will be asked to say whether they are "white", "black or black Irish", "Asian or Asian Irish", or "other, including mixed background". These categories are broken down into further detail.
For example, under the heading "white", respondents will be asked to say whether they are "Irish", "Irish Traveller" or "any other white background".
About 1.5 million forms are being sent to homes around the State. The census will include three other new questions on participation in voluntary activities, family relationships and fertility.
As well as typical demographic matters, other questions include commuting patterns, level of education, existence of a disability and access to the internet.
Everyone in the State must be included in the form, including people staying with friends or relatives, staying in institutions, hospitals, hotels or on board vessels.
Householders and those responsible for institutions, must complete the forms in respect of every adult and child present on census night. CSO senior statistician Aidan Punch said he was hopeful they would record as near to a 100 per cent participation rate as possible.
The census is the first since 2002, which recorded a population of 3.9 million, of which about 6 per cent were foreign nationals. The census typically takes place every five years, however, the 2001 census was delayed due to the outbreak of foot-and-mouth disease.
About 5,000 temporary staff are being employed to carry it out, including 4,500 enumerators. These enumerators are earning on average €2,200 for their work.
As well as being translated into 11 foreign languages, census forms will also be available in large print, Braille and in audio versions.
The Central Statistics Office has also worked with the National Adult Literacy Agency to develop a step-by-step guide to filling out the census form.